The goal of this project is to determine whether ethnic subpopulations (Native Americans, Hispanics, and Micronesians) and recreational anglers in northeastern Oklahoma are exposed to elevated mercury levels resulting from subsistence fishing practices. The study site is located in and around Ottawa County, Oklahoma, in the Grand Lake watershed. This watershed is potentially impacted by local and regional sources of atmospheric mercury deposition, but little is known about the extent of mercury contamination and bioaccumulation in this watershed. Exposure to methyl mercury through consumption of fish is a major public health concern, especially among children and women of childbearing age, due to its role as a neurotoxin and its tendency to biomagnify within food webs. This project was designed in response to community concerns about mercury exposure through consumption of local fish, and will involve a combination of food frequency questionnaires, measurements of hair mercury concentrations as biomarkers of mercury exposure, and measurements of mercury concentrations in commonly-consumed species of local fish. The primary aims of this project are: (1) to determine whether people living in Ottawa County who catch and consume fish from the Grand Lake watershed, particularly members of ethnic populations (Native Americans, Hispanics, Micronesians), have higher body burdens of mercury compared to other residents of the same geographic community that do not frequently consume local fish and compared to the general U.S. population; (2) to measure mercury concentrations in fish species commonly caught and consumed from Grand Lake and its major tributaries; (3) to promote safe subsistence fishing by educating community members about mercury concentrations in commonly consumed fish, including information on length, sampling location and season; (4) to develop a community- based education program that will enable community members to participate in the regulatory process at a more informed level; and (5) to promote long-term reductions in mercury concentrations in fish and human exposure by working with state and regional agencies to develop fish consumption advisories that protect subsistence fishers and promote reductions in mercury emissions. Our ultimate goal is to reduce mercury exposure while simultaneously addressing fears about mercury contamination that may unnecessarily limit consumption rates, and to promote subsistence activities that strengthen cultural and family bonds. PUBLIC HEALTH RELEVANCE: This project is designed to determine whether people who eat large amounts of local fish in northeastern Oklahoma are exposed to unsafe levels of mercury through their diet, and to help them find ways to decrease the amount of mercury they consume. This project will involve community participation at all stages of the research, and will emphasize sharing results with the community and developing ongoing educational programs. Ultimately, the results of this project also may be used to develop fish consumption advisories that protect all people, especially those that eat large amounts of fish, and to provide information for government agencies to use in creating regulations to control mercury emissions into the environment.